The present invention relates to the treatment of fluids, and more particularly relates to devices and methods for the treatment of fluids containing contaminants therein and in particular, for the treatment of water.
The treatment of a fluid, and particularly water, with a field is well known in the art. Treatment of water is typically carried out to reduce some of the problems associated with scaling and corrosion of the equipment using the water. In particular, the use of high temperature water in boilers and the like has always caused significant problems and there have been many proposals in the art for treating the water, including the use of chemicals, in order to reduce the problems of scaling and corrosion.
It is known in the art to treat boiler water with either an electrostatic or magnetic field and such devices are commercially available.
The problem of scaling occurs wherein the suspended solids bind together and collect on heat exchange equipment. The degree of the problem will depend on the pH of the water, the operating conditions of the circuit, the source of the water, etc.
As aforementioned, it has been proposed in the art to use high potential electrostatic fields to treat the water such that the particles in suspension become charged and can be attracted/repelled as desired. The same principle is used in other industrial processes such as paint spraying and photocopiers.
The use of magnetic fields to treat water has also been proposed in the art although such devices have not received a large acceptance in the industry. Rather, treatment of the water by chemicals is the norm in many industrial plants.
One particular field wherein a problem exists is in the separation of pollutants by use of a membrane, the principle being that of reverse osmosis. Many such systems are in commercial use in order to purify water. However, one problem which is encountered in such systems is the relatively short life of the membrane due to clogging and/or physical damage by the contaminants.
It is known from U.S. Pat. No. 4,443,320 to provide electrodes which extend into a fluid carrying conduit.
It is an object of the present invention to provide an improved reverse osmosis system wherein membrane life may be enhanced.
It is a further object of the present invention to provide a novel; electrostatic device for the treatment of water.
It is a further object of the present invention to provide a magnetic device for the treatment of a fluid.
It is a still further object of the present invention to provide improvements in processes and apparatuses which use fields to treat a fluid.
According to one aspect of the present invention of in a device for treating a fluid comprising an outer elongated conduit, an inner coaxial conduit, a fluid passageway being defined intermediate the outer elongated conduit and the inner coaxial conduit, means for creating an electrostatic field within the passageway, there is provided the improvement comprising baffle means mounted in the fluid passageway; a plurality of electrode needles in electrical communication with the outer conduit, the electrode needles extending inwardly towards the inner coaxial conduit, and a power source operatively connected to the outer conduit and the needles to create an intense electric discharge similar to a corona effect. Alternately, the outer conduit and electrode needles are connected to ground and a DC power source is connected to the inner conduit.
In a further aspect of the present invention, there is provided a method for treating fluid comprising the steps of supplying the aforementioned fluid treating device and passing the fluid through the fluid passageway and applying a DC voltage to the needles to create an intense electric discharge similar to a corona effect.
In a still further aspect of the present invention, there is provided a method for prolonging the life of a membrane in a reverse osmosis system wherein a fluid is passed over the membrane, the method comprising the step of passing the fluid through a field to create a positive charge on any particulate matter in the fluid.
Various types of closed (or partially closed) loop systems wherein scaling and corrosion causes problems are known. One may include heating and air conditioning equipment such as hot water or steam boilers, cooling water towers, heat pumps, refrigeration equipment, distillers, etc. The use of a polarization system influences the contaminants within the fluid With the present invention, one is able to polarize die contaminant molecules in a manner which changes their ability to affect the system. In particular, these contaminant particles are kept in an ionic form for reasons which are discussed hereinbelow.
The closed loop system may be any conventional and would normally include, in the case of hot water or steam, a boiler, associated conduits for recirculating the fluid, a pump and other conventional components including valves and the like. According to the present invention, there is provided a polarization system to inhibit the deposition of contaminants.
In a purification system using membranes such as in reverse osmosis, the fluid (hereinafter referred to as water) passing over the surface of the polymer membrane creates a situation wherein the membrane surface becomes positively charged with transfer of electrons to the water which thereby becomes negatively charged and a conductor. Neutral molecules such as calcium carbonate tend to be destabilized by the induction of the negative charges and will generally be attracted to the membrane surface and/or any other positively charged surface. In this state, the calcium carbonate is generally in the form of small needles which can have a deleterious effect on the surface of the membrane. As time goes along, the membrane becomes clogged and damage occurs to the surface.
With the use of a polarization device, the device, in one embodiment, provides a positive charge to the water. Molecules of, for example, calcium carbonate which are normally neutral, are reorganizing their electro-chemical bonds. The small sharp needles of calcium carbonate tend to gather together in small porous balls which carry a positive charge. These small porous balls, when they reach the surface of the membrane, absorb and neutralize negative ions and then there is a natural ionic repulsion between the limestone balls and the surface. A similar process may be carried out with other contaminants including bio-contaminants.
The magnetic reactor is most suitable for treating relatively small volumes of water as the cost of magnets can be substantial. Preferably, such a device would be used only for treating volumes up to approximately 80 litres per minute.
The outer conduit may be made of any suitable material including stainless steel or plastic, the material being capable of withstanding the corrosion, pressure and temperatures required.
The magnetic portion of the device may be suitably encased within the inner conduit which is preferably of a stainless steel having a minimum thickness. The magnets are preferably of the AlNiCo type. The arrangement is such that the inner conduit represents approximately half of the total diameter of the outer conduit. Although different sizing may be used, generally magnets may be approximately 2-3 centimetres in diameter and 2-3 centimetres long. The magnets are arranged such that similar poles face each other and thus have a repelling force towards each other.
As above mentioned, there are provided baffle means which are designed to impart a spiral motion to the fluid being passed therethrough. Preferably, the baffles are such that the water will pass through 360 degrees in 1xc2xd times the magnet length. As the water passes through the passageway, there is set up an electromagnetic force in the fluid. This in turn will charge the contaminated molecules. These contaminants, which may be for example, calcium carbonate, then tend to form small porous balls which carry a positive charge.
In the electrostatic field embodiment, there is provided a device, which in addition to creating an electrostatic field, combines the same with electrodes protruding into the passageway to provide a localized energy content.
The electrostatic generator may operate at between xe2x88x9212 kV DC to xe2x88x9250 kV DC with a current of between 250 mA to 10 mA. It is also possible to use positive voltage if circumstances require the same.
According to the present invention, one can use different types of polarization devices in different water treatment apparatuses such as reverse osmosis systems and closed loop boiler systems.
In the instant specification, reference has been made to water as being the fluid most commonly treated. It will be understood that other fluids may likewise be treated. Such fluids can include, for example, liquids and vapours.
It will also be understood that the polarization devices of the present invention may be used either singly or in combination if so desired.